I would like to be a mod, yes. Been around the game since it was in beta and I'm also the modder that keeps it somewhat alive today. I don't expect too many runs to be submitted but I'm happy to help :)

It is technically possible, yes

Cool, thanks. Maybe we get the already requested missing difficulties and modes some day :)

Yes, in PC is "easy" to have a clean save.

I noticed that the speedrun page has also a space to upload saves, maybe it would be useful to have there a clean save?

(It's under Resources>Saves)

+1 for weekly challenges and Scramble

Yep, with Rift Rush, enemies not only get speed boost, they also ignore guardians/players